Cumberland has just finished his second season with the Kobe Steel team and is going back for another year, with pre-season training starting next month.
But he said tough economic times had made a big impact on Japanese rugby and many players had been let go as money worries started to affect teams.
"The global recession has really hit hard.
"Some of those companies that pour money into rugby and do not get a lot of return out of it have been forced to cut costs," he said.
"Unfortunately, that meant a lot of guys who were at the end of their contracts did not get them renewed."
Cumberland (45) said he was one of the lucky ones, continuing to be the forwards coach for the Kobe Steel side, which finished just outside the top four in the Japanese league last year.
"We played well but just did not perform quite as well as we expected.
"The forwards played well and got enough ball but we lacked a bit of penetration in the midfield."
Cumberland does not suffer for lack of New Zealand company at Kobe.
Former Otago and Highlanders captain Josh Blackie plays for the side, while Southland midfielder Jason Kawau and former Highlanders loose forward George Naoupu are joining next season.
Former Springbok first five Andre Pretorius was going to link with the team but has badly damaged his hamstring and his future is in doubt.
Cumberland, who played 81 games for Otago as a prop, said Japanese sides enjoyed throwing the ball around and had quick outside backs.
The forwards lacked size and tended to shy away from tackling large opponents, but Japanese teams were getting better at the set piece.
Many of the key decision-makers on the field were still foreigners, he said, so many of the Japanese were not getting exposure to the critical positions on the field.
"It can be frustrating at times because they don't have that same instinctive skills as the guys here.
"But they are wonderful to coach.
"They are very, very keen, train hard and have a wonderful work ethic."
Cumberland said the standard of the top sides would be similar to the middle reaches of the national provincial championship.
Cumberland's family - wife Pam and sons Matt (20) and Taylor (13) - have remained in Dunedin and travel to Japan in the holidays to catch up on some family time.
"With all the time I was away with the Super 14 and the NPC, it works out that we have more time together now."
Cumberland said he enjoyed the Japanese environment but did not know what his plans were after next season.
